Reinforcement block construction process and piles prolongation for dynamic pile tests, metallic mold and reinforcement block

ABSTRACT

A reinforcement block construction process and piles prolongation for dynamic pile tests, metallic mold and reinforcement block, which refers to a reinforcement block construction process and piles prolongation for performing dynamic pile tests, implemented by the use of a laminar metallic structure appropriately constructed, in which are provided holes for inserting the anchor bolts, and later on the electronic sensors is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Brazilian Application No. 10 2015 000896 1, having a filing date of Jan. 14, 2015, the entire contents of which are hereby incorporated by reference.

FIELD OF TECHNOLOGY

The following refers to a reinforcement block construction process and pile prolongation for High Strain Dynamic Pile Testing—HSDPT—or dynamic pile tests made with the PDA equipment (“Pile Driving Analyzer”) on foundation piles of construction sites. The following also refers to a metallic mold for the construction of a reinforcement block and to the reinforcement block obtained by this very process.

BACKGROUND

The High Strain Dynamic Pile Testing—HSDPT—also known as dynamic pile tests made with the PDA equipment is the method to monitor and record measurements of physical and mathematical parameters through specific electronic sensors fixed on top of the foundation piles. In the case of excavated piles or cast “in situ” piles, the construction of a reinforcement block and prolongation of the piles is indispensable and necessary, in order to allow the installation of electronic sensors, the dynamic pile tests and to guarantee the integrity of the piles, checking the load capacities during the testing.

After breaking the top, the piles are leveled to ground and an extension block is constructed over the top that should be perfectly upright (without leanings or deformations), also with a leveled top and adequate resistance to support strokes applied by an impact device or a hammer. The strokes are applied directly on top of the reinforcement block, which must be positioned and fixed so that its axis is centered with the axis of the pile.

The impact device is positioned above the reinforcement pile-block assembly, containing a load with adequate dimensions and weight that falls in free fall over the top of the block, many times as necessary. The applied strokes generate shock waves that will be captured by the electronic sensors and produce the expected results of the dynamic pile testing.

Generally, being temporary, reinforcement blocks and prolongation of the piles are built in a rudimentary and poor way. They are usually made of cardboard molds in cylindrical shapes with the same diameter of the pile, which are positioned after the installation of the reinforcement steel in the center, and then the concrete is dropped inside. A time interval is necessary to achieve the adequate resistance of the concrete, and then this cardboard mold is removed and discarded, which means it cannot be used again.

After the concrete curing the electronic sensors are attached to the lateral surface of the reinforcement block, through holes made by manual drills. However, the adequate location and appropriate installation of the electronic sensors are necessary in order to perfectly capture the shock waves produced by the strokes applied on top of the reinforcement block.

In some cases, the reinforcement block lacks appropriate technical and design specifications to obtain the parameters for the correct interpretation of the pile test. Nonconformities may generate inconsistent and, therefore, unreliable results. The incorrect attachment of the electronic sensors is another factor that may also contribute for the generation of inaccurate results.

In addition, the construction of the reinforcement block, when poorly specified, besides being inaccurate, causes time consuming services as it invariably delays the pile testing, resulting in delays on the entire work at the construction site.

Embodiments of the present invention solve the problems inherent to the construction of the reinforcement blocks, with a predetermined location of the holes for the attachment of the electronic sensors, perfectly suitable to the templates needed to perform the dynamic load test in a fast and accurate way and with reliable results

SUMMARY

One aspect of the embodiments of the present invention are to characterizes the process for the construction of a reinforcement block and piles prolongation which provides a quick, simple and accurate dynamic pile test, resulting in a perfectly appropriate reinforcement block which facilitates and accelerates the test in order to obtain the necessary results.

Another aspect of embodiments of the present inventionare to characterize the process for the construction of a reinforcement block and pile prolongation that already complies with the correct location of the holes for the attachment of the electronic sensors resulting, therefore, in a more accurate and reliable result of the dynamic pile test.

Another aspect of embodiments of the present invention are to characterize the metallic mold for the construction of a reinforcement block and pile prolongation, endowed with constructive and functional details that facilitate the construction of the referred block, making the process fast and simple, and enabling the construction of a block that provides more reliable and accurate test results.

Another aspect of embodiments of the present invention are to characterize the reinforcement block obtained by such a process, which fully meets the parameters required for each test, which enables a perfect monitoring and recording of shock waves by the sensors and a correct data collection, and which can, consequently, produce better results tests.

These aspects are achieved with the use of a metallic mold, pre-shaped and pre-dimensioned, which contains the correct positioning of the holes for a later attachment of the sensors, and which produces the reinforcement block with all the necessary features to generate accurate and reliable results of the pile tests to be performed on the foundation piles.

BRIEF DESCRIPTION

Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

FIG. 1 illustrates a front view of the metallic mold, indicating the predetermined location of the holes for the attachment of the sensors;

FIG. 2 illustrates a view of the metallic mold, in open position;

FIG. 3 illustrates an external detail view of the location of the holes for the attachment of the electronic sensors;

FIG. 4 illustrates an internal detail view of the location of the holes for the attachment of the sensors; and

FIG. 5 illustrates the obtained reinforcement block with the sensors attached on the surface.

DETAILED DESCRIPTION

In detail, embodiments of the present invention refer to a reinforcement block construction process and piles prolongation for performing dynamic pile tests, characterized by being implemented through the use of a laminar metallic structure 1, appropriately constructed and detailed as follows, in which holes are provided for inserting the anchor bolts 4, these holes following a specific dimensioning for the purpose of the obtained reinforcement block.

The anchor bolts 4 are inserted into the holes so that all and each of them are perfectly directed to the center of the metallic mold when the two parts are joined, like a radius in a circumference. This constructive approach is of extreme importance, so that the sensors 5, when inserted into the holes, get the best, the most accurate and the most reliable data by recording the shock waves produced by the strokes applied by the hammer equipment.

The construction process of the reinforcement block 6 and piles prolongation for performing dynamic loading tests, is thus characterized as follows:

1. Positioning of the steel frame (not shown), designed specifically for the test, inside of the two bodies (half-rounds); 2. Setting up the shape of the reinforcement block 6 by joining the two bodies (half-rounds) to each other and fixing the resulting metallic mold 1 to the ground, keeping its perpendicular alignment with the use of rods, already with the steel frame disposed internally inside the metal structure; 3. The anchor bolts 4 are pre-fixed in the holes located in each of the half-round bodies; 4. The inside of the resulting metal structure 1 (two half-rounds perfectly coupled) is filled with concrete, with defined specifications; 5. Waiting for the adequate cure of the concrete so that it reaches the defined resistance, so that the block can withstand the tensions imposed by the hammer strokes and has the ability to transmit these tensions to the top of the pile without damaging it; 6. Unmolding of the metallic mold 1, separating the two metallic parts (two half-rounds); and 7. Anchoring of the sensors 5 to the anchor bolts 4. With the conclusion of the reinforcement block 6, the hammer system is then simply positioned over the block and the application of strokes may be started. The data will be collected by the electronic sensors 5 and transmitted to the equipment that enables the analog visualization of the signals and the digital storage of same, being the operator or technician responsible for monitoring and interpreting the signals and data, and then finalizing the test.

Embodiments of the present invention further refer to a metallic mold 1 for the construction of the reinforcement block 6, consisting of a tubular and laminar metallic mold 1 of an appropriate thickness for each of the possible dimensions, which comprises two bodies of half-round formats, which when united constitute a housing with a cylindrical shape.

Said bodies comprise, at its distal ends, two tangential prolongations adequately distributed along said edges, each of the prolongations 2 provided with a through hole. The unification of the two bodies results in the symmetry of its two prolongations 2, in pairs, so that it is possible to accommodate a latch with a pin format, similar to a screw, fixing the metallic mold.

The bodies are further provided with external longitudinal structural reinforcements 3, to better support the weight and forces applied to it, when they are joined and filled with concrete.

Each of the two bodies comprise, depending on the pile diameter, three or six holes appropriately located and dimensioned, in which elements like anchor bolts 4 are inserted, enabling the correct attachment of the electronic sensors later on. The holes are provided on the surface of one of the bodies, such that the heights and distances between it (the positioning on the half-rounds) follow the specific dimensioning for each diameter of the foundation pile.

Finally, the disclosure refers to the reinforcement block 6 obtained by such a process, correctly designed to perform dynamic pile tests. Said reinforcement block 6 consists of a previously dimensioned steel frame, a previously defined concrete mass, specific for the completion of the loading tests as specified in national standards and of the PDA equipment manufacturer, which involves the steel frame and three or six fixing elements for the sensors 5, attached to the anchor bolts 4, depending on the diameter of the pile. 

1. A reinforcement block construction process and piles prolongation for dynamic pile tests, comprising the following steps: i) providing two bodies and positioning a metal frame inside of the two bodies; ii) setting up a shape of the reinforcement block by joining the two bodies to each other and fixing a resulting metallic mold to the ground, keeping its alignment with the use of rods, already with a metal frame disposed internally inside the metal frame; iii) pre-fixing anchor bolts in holes located in each of the two bodies; iv) wherein the inside of the resulting metal frame is filled with concrete; v) waiting for the adequate cure of the concrete so that it reaches a defined resistance, so that the block can withstand the tensions imposed by the hammer strokes and has the ability to transmit these tensions to a top of the pile without damaging it; vi) unmolding of the metallic mold, separating the two bodies; and vii) anchoring sensors to the anchor bolts.
 2. A metallic mold, comprising a tubular and laminar metallic mold, which comprises two bodies of half-round formats and of an appropriate thickness.
 3. The metallic mold according to claim 2, wherein said bodies comprise, at their distal ends, two tangential prolongations appropriately distributed along said edges, each of the prolongations provided with a through hole.
 4. The metallic mold according to claim 2, wherein said bodies are further provided with external longitudinal structural reinforcements.
 5. The metallic mold according to claim 2, wherein each of the two bodies comprise at least one of three or six holes appropriately located and dimensioned, for the insertion of the anchor bolts, and later on for the attachment of the electronic sensors.
 6. A reinforcement block obtained by the process according to claim 1, wherein comprising a steel frame, a concrete mass which involves the steel frame, and at least one of three or six fixing elements for the sensors, attached to the anchor bolts. 